1. Public health importance of depression in pregnancy. Women of childbearing age are the demographic group at greatest risk for onset and prevalence of depression. Depression is especially common during pregnancy (1), and perinatal depression is a robust risk factor for postpartum depression (2). In addition to the major personal and societal impacts of depression in general, depression during pregnancy is associated with a wide range of negative outcomes for both mothers and infants (3). 2. Concerns Regarding Antidepressant Treatment in Pregnancy. Although antidepressant medication is frequently prescribed to treat depression in pregnancy (4, 5), there are important limitations to pharmacotherapy for perinatal depression. For example, two studies from MHRN sites have used medical records data to examine birth outcomes among infants exposed to antidepressants in utero, finding significantly increased risk for premature delivery, low birth weight, and perinatal complications (6, 7). Many women are reluctant to start or continue antidepressant medications due to concern about impact on the fetus (8). Many pregnant women disconfinue antidepressants, leading to a high rate of depression relapse (9). Pregnant women and their care providers considering antidepressant treatment must weigh the potential benefits of treating depression against the potential risks of neonatal exposure to antidepressants (10). 3. Efficacy and Transportability of Brief Psychotherapies. In contrast, psychological or behavioral interventions offer the promise of efficacy without the concerns regarding fetal or infant exposure to medications (11). Cognitive behavior therapy has been most widely investigated psychotherapy for depression, with recent research suggesting that the simple behavioral component (behavioral activation;BA) demonstrates benefit with respect to pharmacotherapy. In a recent placebo controlled trial conducted by Co-I Dimidjian and colleagues, BA, as compared to pharmacotherapy, was found to have comparable acute phase depression outcomes, superior rates of adherence to care, and enduring benefit following treatment terminafion (12, 13). These results are especially encouraging given that the BA approach may be more easily disseminated outside of specialty mental health care (14). Simon and colleagues also showed that a related intervention (including behavioral activation and brief cognitive re-structuring) was demonstrated to be an effective treatment for depression when delivered in a novel telephone based format (15, 16). 4. Inadequate Evidence Base for Psychological Treatment of Perinatal Depression. There is a surprising paucity of research examining non-pharmacological interventions among depressed pregnant women. In fact, only two randomized clinical trials in the US have been published (17, 18). Findings were promising;however, both were limited by small sample size and restriction of entry to low income women. Available data are not adequate to guide treatment decisions forthe general population of pregnant women with depression. 5. Pressing Need for Effectiveness Research. Research to inform pafients'and providers'decisions regarding depression treatment during pregnancy must consider overall effectiveness rather than simple efficacy. While pregnant women with depression may express a preference for psychotherapy over medication (see Preliminary Studies below), the stresses and competing priorities of pregnancy and postpartum create significant barriers to participation in traditional mental health treatments. Research must address the question "Will this treatment prove acceptable and effective when delivered by real-worid providers to typical pafients treated in everyday practice settings?" rather than "Will this treatment prove efficacious when delivered by research clinicians to highly motivated volunteers seeking treatment through a research center?" 6. Summary and Study Rationale. The significance of the proposed project, thus, is supported by four key points as evident in the literature reviewed here and in our own work (Preliminary Studies). Specifically, 1) untreated antenatal depression has serious adverse consequences for women and their offspring, 2) pharmacotherapy, the current standard of care, presents women and their care providers with complex riskbenefit decisions, 3) BA and related non-pharmacological treatments have demonstrated efficacy among depressed adults and are transportable to routine care settings, and 4) few studies have examined such intervenfions with pregnant women. The proposed MHRN provides an ideal setting in which to test innovative interventions for depressed pregnant women.